Hello gents. I recently replaced all the speakers in my 2010 sedan cobalt with the infinity primus's, 6.5 coaxial in front and 6x9 3 way speakers in the back deck. Now the issue I ran into is that the back 6x9s have no bass. I've been considering putting in the stock 6x9s back in because they have much more bass. Another thing I noticed is the stock 6x9s have a foam liner on top and bottom. I'm pretty sure it will, but do you guys think that if I just line the infinities with foam it will help or what have you guys experienced? Thanks.